FIELD OF THE INVENTION
This invention relates generally to automatic injectors, and more specifically to automatic injectors adapted for injecting a medicament into the rectum of a subject.
While the rectal administrator of the present invention can be used to treat any type of physical ailment which can be treated by injecting a medicament into the rectum, the present invention is primarily concerned with the treatment of febrile seizures. Febrile convulsions are the most common type of seizure occurring in children. In fact, such seizures occur in about 2 to 4 percent of all children. In addition, approximately one third of those children who suffer a febrile seizure also have at least one relapse.
Recent studies have shown the benefits of treating febrile convulsions with rectal diazepam (while other anti-convulsant drugs, such as phenobarbitone, valproate, and clonazepam have also been rectally administered to treat febrile convulsions, heretofore, diazepam has been the drug of choice). It can be appreciated that during an acute febrile seizure, it is extremely important for the diazepam to be administered as quickly as possible. Though febrile convulsions generally carry good prognosis, the attacks can lead to permanent neurological damage and even death.
Abundant pharmacokinetic evidence suggests that rectal diazepam in solution may effectively treat both ongoing and acute seizures and be an advantageous alternative to i.v. diazepam. Not only is rectal administration less painful and easier to administer, but it has been shown that absorption of diazepam is more rapid when administered rectally than when administered intravenously. With rectal administration of diazepam, presumed anticonvulsant levels are attained within minutes, especially in infants and small children.
It can be appreciated, therefore, that a limiting factor in the effectiveness of rectal diazepam is the ease and speed by which it can be administered.
Thus far, the typically available rectal administrator, as disclosed in U.S. Pat. Nos. 627,658, 4,846,801, and 1,775,329, has been manufactured for non-emergency treatment of hemorrhoids, fissures, ulcerations, eczema, and other pathological conditions of the anus and rectum. Such injectors include an outer sleeve-like body in which a medicament may be placed. The body has a drug delivery orifice at one end thereof and a plunger receiving portion at the other end thereof. An elongate plunger is fittable into the plunger receiving end of the body and is used to manually administer the drug through the drug delivery orifice by manually advancing the plunger through the body.
These rectal administrators have several disadvantages. First, the medicament must first be placed into the sleeve-like body before the elongate plunger can be fitted into the receiving end of the body (the administrators are not normally pre-filled). Because these administrators are not adapted for emergency use, the time constraints associated with filling the body with a medicament is of no consequence.
Second, even after the body of the conventional rectal administrator is filled with medicament, the user must still properly insert the separately provided elongate plunger into the receiving end of the body.
Third, even after the administrator is filled and arranged to have the forward end of the elongate plunger correctly aligned with the body, the total length of the assembly is quite long, requiring two hands to be used during the procedure of advancing the elongate plunger through the body; a first hand to grab the body and insert it into the rectum and a second hand to advance the plunger while the first hand maintains the body in place.
Fourth, even in the instance in which such an administrator may be manually pre-filled with medicament and pre-assembled with the elongate plunger positioned at the open end of the body, the total length of such an assembly would make it impractical to carry in one's pocket or the like.
Fifth, in the instance in which rectal diazepam is self administered, it can be appreciated that it would be quite difficult for a patient having a seizure, not only to insert the injector into his or her own rectum, but also to advance the plunger through the body to administer the drug.
Sixth, in the instance in which an adult is administering the drug into the rectum of a child, the time of such administration is limited by the need to manually advance the plunger through the body; a procedure which may take several valuable seconds.
Therefore, there exists a need for a compact, pre-filled rectal administrator having an automatic means of dispensing the medicament from the rectal administrator's body to facilitate the administrative procedure.
It is an object of the present invention to fulfill the need expressed above by providing an inexpensive rectal administrator which is adapted to automatically dispense medicament after being inserted into the user's rectum. In accordance with the principles of the present invention, this objective is achieved by providing a rectal administrator having a body with an administrative portion adapted to be inserted into a subject's anus. A charge of medicament is disposed within the body, and the administrative portion has at least one passage through which the medicament can exit the body. A plunger is disposed in the body and is movable from a first position to a second position within the body to dispense the medicament from the body through the at least one passage. A releasable energy source is mounted within the body so as to be released in response to a predetermined actuating procedure. The releasable energy source moves the plunger from the first position to the second position to dispense the medicament from the body through the at least one passage when released in response to the predetermined actuating procedure.
These and other objects of the present invention will become more apparent during the course of the following detailed description and claims.
The invention may be best understood with reference to the accompanying drawings wherein illustrative embodiments are shown.